If you feel like want to strengthen the project team and do more or less regular work you are welcome, let me know and you get the main repository write access. For unregular contributions it is better to fork and to work with the pull requests.

Sorry for not posting for so long. Thanks to seb4stien the add-on updater is reality now. See the new Wiki page on [http://freeplane.sourceforge.net/wiki/index.php/How_to_publish_add-ons how to publish add-ons].

@Sebastien: Could you please check and correct the wiki page? I have used your text from the discussion page.